KR20150001115A - Multi-layer resistor structure and Inertial Sensor having The Same - Google Patents

Abstract

According to the present invention, a multi-layer piezoresistors structure includes a plurality of piezoresistors which is disposed to be separated for a stacked direction and an oxide film which is formed among the piezoresistors, wherein the oxide film forms a via hole to be connected to the piezoresistors electrically by injecting a conductive material into the via hole. The present invention increases sensitivity without increase of power consumption and secures the length of the piezoresistors due to the multi-layer piezoresistor structure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a multilayer resistor structure and an inertial sensor having the same,

The present invention relates to a multi-layered piezoresistive structure and an inertial sensor having the same.

In recent years, the inertial sensor has been widely used in military applications such as air bag, ESC (Electronic Stability Control), and automobile black box (black box) for the prevention of camera shake of a camcorder, motion sensing of a mobile phone or a game machine from a military use such as a satellite, a missile, , Navigation and so on.

In order to measure acceleration and angular velocity, such an inertial sensor employs a configuration in which a mass body is bonded to an elastic substrate such as a membrane, which is generally a flexible member. Through the above configuration, the inertial sensor can calculate the acceleration by measuring the inertial force applied to the mass, or calculate the angular velocity by measuring the Coriolis force applied to the mass.

Specifically, a method of measuring the acceleration using the inertial sensor will be described as follows. First, the acceleration can be obtained by Newton's law of motion "F = ma", where "F" is the inertial force acting on the mass, "m" is the mass of the mass, and "a" is the acceleration to be measured. The acceleration (a) can be obtained by detecting the inertial force F acting on the mass and dividing it by the mass m of the mass, which is a constant value.

On the other hand, as an example of an inertial sensor, a pressure resistance type acceleration sensor according to the related art including prior art documents is provided with a piezoresistive body on a membrane (diaphragm) in order to sense displacement of a mass body. However, the inclusion of a piezoresistive body as a single layer has a limitation in ensuring the length of the piezoresistive body, and has a limitation in detecting the displacement of the mass.

US 20030209075 A

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is a first aspect of the present invention to provide a piezoresistive device having a multilayer structure in a lamination direction, Thereby providing a multi-layered piezoresistive structure for an inertial sensor capable of improving sensitivity without increasing power consumption.

The second aspect of the present invention is to provide an inertial sensor having a multi-layered piezoresistive structure to improve sensing sensitivity and efficiency, as well as being small and lightweight.

A multilayer piezoresistive structure according to a preferred embodiment of the present invention includes a plurality of piezoresistors disposed to be spaced apart from each other in a stacking direction and an oxide film formed between the plurality of piezoresistors, A via hole is formed, and a conductive material is injected into the via hole, so that the plurality of piezoresistors are electrically connected.

Furthermore, in the multilayer piezoresistive structure according to the embodiment of the present invention, the plurality of piezoresistors are composed of the first piezoresistor and the second piezoresistor.

Further, in the multilayer piezoresistive structure according to an embodiment of the present invention, the first and second piezoresistors are formed on the silicon substrate, respectively, and the upper portion of the silicon substrate And a silicon substrate on which the first piezoresistive body is formed is formed on the oxide film.

Further, in the multilayer piezoresistive structure according to an embodiment of the present invention, an electrode is formed on an upper portion of the silicon substrate on which the first piezoresistor is formed, and the first piezoresistor is electrically connected to the electrode.

In the multilayer piezoresistive structure according to an embodiment of the present invention, a via hole is formed in the silicon substrate on which the first piezoresistive member is formed to connect the first piezoresistive member to the electrode, and a conductive material is injected into the via hole. And the first piezoelectric resistor is electrically connected to the electrode.

In the multilayer piezoresistive structure according to an embodiment of the present invention, an oxide film that partially covers the electrode and covers the silicon substrate on which the first piezoresistive member is formed is formed on the electrode and the silicon substrate.

The inertial sensor having a multilayer piezoresistive structure according to an embodiment of the present invention includes a flexible portion, a mass connected to the flexible portion, and a support portion connected to the flexible portion and supporting the mass in a floating state so as to be displaceable And the flexible portion is formed with a multilayer pressure resistance structure formed on one surface portion of the flexible portion so as to detect a displacement of the mass body, wherein the multilayer pressure resistance structure includes a plurality of And an oxide film formed between the plurality of piezoresistive bodies, wherein the oxide film is formed with a via hole for connecting the plurality of piezoresistors, and a conductive material is injected into the via hole, so that the plurality of piezoresistors are electrically .

Further, in the inertial sensor having the multilayer piezoresistive structure according to the embodiment of the present invention, the plurality of piezoresistors are composed of the first piezoresistor and the second piezoresistor.

In the inertial sensor having the multi-layered piezoresistive structure according to an embodiment of the present invention, the first and second piezoresistors are formed on the silicon substrate, and the second piezoresistive body is formed An oxide film is formed on the silicon substrate and a silicon substrate on which the first piezoresistive body is formed is formed.

In the inertial sensor having the multilayer piezoresistive structure according to an embodiment of the present invention, an electrode is formed on an upper surface of the silicon substrate on which the first piezoresistive body is formed, and the first piezoresistor is electrically connected to the electrode do.

In the inertial sensor having the multi-layered piezoresistive structure according to an embodiment of the present invention, a via hole for connecting the first piezoresistive member and the electrode is formed on the silicon substrate having the first piezoresistive member formed thereon, Conductive material is injected so that the first piezoelectric resistor is electrically connected to the electrode.

In an inertial sensor having a multilayer piezoresistive structure according to an embodiment of the present invention, an oxide film that partially covers the electrode and covers the silicon substrate on which the first piezoresistive body is formed is formed on the upper portion of the electrode and the silicon substrate .

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to the present invention, the piezoresistive body is formed in a multi-layered structure with respect to the lamination direction so that the length of the piezoresistive element can be ensured and thus can be realized as a high resistance material. Thus, sensitivity can be improved without increasing power consumption, So that the sensing sensitivity and efficiency can be improved, and an inertial sensor that can be realized with a small size and a light weight can be obtained.

1 is a cross-sectional view schematically showing a multilayer piezoresistive structure according to an embodiment of the present invention;
2 is a schematic plan view of an inertial sensor according to an embodiment including the multilayer piezoresistive structure shown in Fig.
Figure 3 is a schematic AA cross-sectional view of the inertial sensor shown in Figure 2;

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Also, the terms "first "," second ", and the like are used to distinguish one element from another element, and the element is not limited thereto. In the following description of the present invention, a detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view schematically showing a multilayer piezoresistive structure according to an embodiment of the present invention. As shown in the figure, the multilayer piezoresistive structure 10 includes a plurality of piezoresistors 11a and 11b, oxide films 12a and 12b, silicon substrates 13a and 13b, and electrodes 14.

More specifically, the plurality of the piezoresistors 11 are formed on the silicon substrates 13a and 13b so as to be spaced apart from each other in the stacking direction, and the silicon substrate may be provided with a via hole connecting the plurality of piezoresistors. A conductive material is injected into the via hole and the plurality of piezoresistors 11 are electrically connected.

In one embodiment, the plurality of the piezoresistors 11 may include a first piezoresistor 11a and a second piezoresistor 11b. The first piezoresistor 11a and the second piezoresistor 11b are formed on the silicon substrates 13a, 13b so as to be spaced apart from each other in the stacking direction, and an oxide film 12b, which is an insulating layer, is formed in the spaced apart spaces.

That is, an oxide film 12b is disposed on the second piezoresistor 11b in the stacking direction, and a first piezoresistor 11a is disposed on the oxide film 12b.

A via hole is formed in the oxide film 12b to connect the first and second piezoresistors 11a and 11b and a conductive material is injected into the first and second piezoresistors 11a and 11b, Are electrically connected.

An electrode 14 is formed on the upper portion of the silicon substrate 13a on which the first piezoresistor 11a is formed with respect to the stacking direction.

The electrode 14 is electrically connected to the first piezoresistor 11a electrically connected to the second piezoresistor 11b and transmits an external power or an electric signal to the piezoresistor through the first piezoresistor 11a, And to transmit the detection signals of the second piezoresistors 11a and 11b to the outside.

For this, a via hole in contact with the first piezoresistive member 11a is formed on the silicon substrate 13b, and a conductive material is filled in the via hole, so that the first piezoresistor 11a and the electrode 14 are electrically connected.

An oxide film covering the silicon substrate (13a) on which the first piezoresistive member (11a) is formed is partially covered with the electrode (14a) so as to partially expose the electrode (14) May be formed on the top of the substrate.

According to the above-described construction, the piezoresistive body has a multi-layered piezoresistive structure with respect to the lamination direction, and thus, the length of the piezoresistor can be secured and realized as a high resistance body. .

Fig. 2 is a schematic plan view of an inertial sensor according to an embodiment including the multilayer piezoresistive structure shown in Fig. 1, and Fig. 3 is a schematic A-A cross-sectional view of the inertial sensor shown in Fig.

As shown, the inertial sensor 100 includes a flexible portion 110, a mass 120, and a support portion 130. The flexible part 110 is formed in a plate-like shape and is made of a flexible substrate such as a membrane or a beam having elasticity so that the mass body 120 can cause displacement.

The mass body 120 is coupled to one surface of the flexible portion 110, and displacement occurs due to an inertial force, an external force, a Coriolis force, a driving force, or the like.

The support portion 130 is coupled to one surface of the flexible portion and is supported in a floating state so that the mass body 120 can be displaced.

At this time, the mass body 120 is positioned at a central portion of the flexible portion 110, the support portion 130 is formed into a hollow shape, the mass body 120 is positioned in the hollow portion so as to be displaceable, The support portion 130 is located at the edge portion of the flexible portion 110, thereby securing a space in which the mass body 120 can cause displacement.

In addition, the mass body 120 may be formed in a square pillar shape, and the support portion 130 may have a cylindrical shape or a square pillar shape. In addition, the shape of the mass body 120 and the support part 130 is not limited thereto, and may be formed in all shapes known in the art.

The flexible portion 110, the mass body 120, and the support portion 130 may be formed by selectively etching an SOI (Silicon On Insulator) substrate that can be easily processed by a MEMS (Micro Electro Mechanical Systems) process.

Therefore, a silicon oxide film (not shown) of the SOI substrate may remain between the mass body 120 and the flexible portion 110 and between the support portion 130 and the flexible portion 110. However, the flexible portion 110, the mass body 120, and the support portion 130 are not necessarily formed by etching the SOI substrate, but may be formed by etching a general silicon substrate or the like.

Also, the support part 130 may further include an electrode pad 131 for inputting and outputting a sensing signal.

Hereinafter, the technical structure, shape, organic bonding, and effects of the flexible portion of the inertial sensor according to the present invention will be described in more detail.

3, the flexible portion 110 includes a first piezoresistor 111a ', a second piezoresistor 111a', an oxide film 111b 'and 111b' (111c ', 111c ") and an electrode 111d.

More specifically, the first piezoresistors 111a 'and the second piezoresistors 111a', which are a plurality of piezoresistors, are formed on the silicon substrates 111b 'and 111b' so as to be spaced apart from each other in the laminating direction, The oxide film 111b "as an insulating layer is formed between the one-piezoresistive element 111a 'and the piezoelectric resistive element 111a ".

That is, an oxide film 111b "is disposed on the second piezoresistor 111a" in the stacking direction, and a first piezoresistor 111a 'is disposed on the oxide film 111b ".

A via hole connecting the first piezoresistive member 111a 'and the second piezoresistive member 111a "is formed in the oxide film 111b ", and a conductive material is injected into the first piezoresistor 111a' The resistor 111a "is electrically connected.

An electrode 111d is formed on the upper portion of the silicon substrate 111b 'on which the first piezoresistive member 111a' is formed with respect to the lamination direction.

The electrode 111d is electrically connected to the first piezoresistive member 111a 'electrically connected to the second piezoresistor 111a', and transmits an external power or an electric signal to the piezoresistor through the first piezoresistor 111a ' To transmit the detection signals of the one-piezoresistive element 111a 'and the second piezoresistive element 111a " to the outside.

For this, a via hole in contact with the first piezoresistive member 111a 'is formed on the silicon substrate 111b', and a conductive material is injected into the via hole, so that the first piezoresistor 111a 'and the electrode 111d are electrically .

In order to partially expose the electrode 111d to the outside with respect to the stacking direction, an oxide film covering the electrode 111d and covering the silicon substrate on which the first piezoresistive body is formed is formed on the upper portion of the electrode and the silicon substrate As shown in FIG.

Accordingly, the inertial sensor according to the embodiment of the present invention may be configured such that when the mass body 120 is displaced due to an external force or the like, the first and second piezoresistors 111a 'and 111a " The resistance of the flexible portion 111 is changed according to the elastic deformation of the flexible portion 111. At this time, the length of the piezoresistive body can be secured by the first and second piezoresistors, It is possible to improve the sensitivity and improve the sensing sensitivity and efficiency as well as to obtain an inertial sensor that can be realized with a small size and a light weight.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be apparent that modifications and improvements can be made by those skilled in the art. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: Multi-layered piezoresistance structure 11: Multiple piezoresistors
11a: first piezoelectric resistor 11b: second piezoelectric resistor
12a, 12b: oxide (oxide) 13a, 13b: silicon substrate
14: Electrode
100: inertia sensor 110: flexible portion
120: mass body 130:
111: Multilayer piezoresistive structure
111a ': first piezoresistor 111a': second piezoresistor
111b ', 111b'': an oxide film 111c', 111c '':
111d: electrode

Claims (12)

A plurality of piezoresistors disposed so as to be spaced apart from each other in a stacking direction; And
And an oxide film formed between the plurality of piezoresistors,
A via hole for connecting the plurality of piezoresistors is formed in the oxide film,
And a plurality of piezoresistors are electrically connected to the via holes by injecting a conductive material into the via holes.
The method according to claim 1,
Wherein the plurality of piezoresistors are composed of a first piezoresistor and a second piezoresistor.
The method of claim 2,
The first and second piezoresistors are respectively formed on a silicon substrate, an oxide film is formed on an upper portion of the silicon substrate on which the second piezoresistive member is formed, and a first piezoresistive member is formed on the oxide film Wherein a silicon substrate is formed.
The method of claim 3,
Wherein an electrode is formed on an upper portion of the silicon substrate on which the first piezoresistive member is formed, and the first piezoresistor is electrically connected to the electrode.
The method of claim 4,
A silicon substrate on which the first piezoresistive body is formed is provided with a via hole for connecting the first piezoresistive element and the electrode and a conductive material is injected into the via hole so that the first piezoresistive element is electrically connected to the electrode Multi - layer Resistive Structure for Inertial Sensors.
The method of claim 5,
Wherein an oxide film that partially covers the electrode and covers the silicon substrate on which the first piezoresistive body is formed is formed on the electrode and the silicon substrate.
Flexible portion;
A mass connected to the flexible portion; And
And a support portion connected to the flexible portion and supporting the mass body in a floating state so as to be displaceable,
The flexible portion is formed with a multilayer pressure resistance structure formed on one surface portion of the flexible portion to detect displacement of the mass body,
Wherein the multilayer piezoresistive structure comprises: a plurality of piezoresistors disposed so as to be spaced apart from each other in a stacking direction in which the flexible portion is coupled to the mass body; And
And an oxide film formed between the plurality of piezoresistors,
A via hole for connecting the plurality of piezoresistors is formed in the oxide film,
Conductive material is injected into the via hole and the plurality of piezoresistors are electrically connected to each other.
The method of claim 7,
Wherein the plurality of piezoresistors are composed of a first piezoresistor and a second piezoresistor.
The method of claim 8,
The first and second piezoresistors are respectively formed on a silicon substrate, an oxide film is formed on an upper portion of the silicon substrate on which the second piezoresistive member is formed, and a first piezoresistive member is formed on the oxide film Wherein a silicon substrate is formed.
The method of claim 9,
Wherein an electrode is formed on an upper portion of the silicon substrate on which the first piezoresistor is formed, and the first piezoresistor is electrically connected to the electrode.
The method of claim 10,
Wherein a via hole connecting the first piezoresistive member and the electrode is formed on a silicon substrate on which the first piezoresistive member is formed and a conductive material is injected into the via hole to electrically connect the first piezoresistive member to the electrode. sensor.
The method of claim 11,
Wherein an oxide film covering the electrode and covering the silicon substrate on which the first piezoresistive body is formed is formed on the electrode and the silicon substrate.

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